This invention relates to devices and methods for positioning a patient on the table of a radiation imaging machine, radiation treatment machine and the like. More particularly, the invention relates to a device and method for supporting and holding a patient in a stable lateral decubitus position on such a table.
The advantages of laterally scanning patients with x-ray devices for diagnostic purposes are well known. For instance, a paper by R. Mazess et al., "Measurement of Spine Density in the Lateral Position" presented at the First Joint Meeting of the ICCRH/ASBMR, Montreal, Canada, September 1989, discloses the use of lateral scanning for measurement of bone density in the lumbar spine region with a bone densitometer.
When patients are monitored for changes in bone density at regular intervals over a period of time, it is important for them to be in the same position and orientation for each measurement so that there is a common reference. Such a common reference is also important when different patients' measurement are compared for diagnostic purposes.
At the present time, lateral scanning usually is performed with the patient lying in the supine position. The most commonly used approach for accommodating lateral scanning is to make a C-arm carrying a radiation source and detector rotatable so that it and the radiation source and detector can be rotated 90.degree. from the vertical. Such a capability complicates the construction of the densitometer and adds a significant cost.
It can be quite painful for patient with osteoporotic fractures to lie in the supine position on the table of a densitometer or the like for the period of time required for scanning, which typically is 5-10 minutes. On the other hand, most of such patients can lie on the table in a lateral decubitus position (i.e. on their side) with much less pain, particularly if their legs and knees are flexed into a comfortable position.
For these and other reasons, there is a need for a device and method for conveniently and repeatedly positioning patients in a comfortable, lateral decubitus position on the table of a densitometer or the like and maintaining the patient in that orientation for the period time required for scanning.